diff --git a/scripts/manual/run_server_to_rc_mode_matrix.sh b/scripts/manual/run_server_to_rc_mode_matrix.sh
index ec61d41..42072d8 100755
--- a/scripts/manual/run_server_to_rc_mode_matrix.sh
+++ b/scripts/manual/run_server_to_rc_mode_matrix.sh
@@ -52,6 +52,7 @@ LESAVKA_SERVER_RC_RECONFIGURE_SETTLE_SECONDS=${LESAVKA_SERVER_RC_RECONFIGURE_SET
 LESAVKA_SERVER_RC_RECONFIGURE_VERBOSE=${LESAVKA_SERVER_RC_RECONFIGURE_VERBOSE:-0}
 LESAVKA_SERVER_RC_PROMPT_SUDO_EARLY=${LESAVKA_SERVER_RC_PROMPT_SUDO_EARLY:-1}
 LESAVKA_SERVER_RC_REMOTE_SUDO_PASSWORD=${LESAVKA_SERVER_RC_REMOTE_SUDO_PASSWORD:-}
+LESAVKA_SERVER_RC_START_DELAY_SECONDS=${LESAVKA_SERVER_RC_START_DELAY_SECONDS:-0}
 LESAVKA_SERVER_RC_WAIT_TETHYS_READY=${LESAVKA_SERVER_RC_WAIT_TETHYS_READY:-1}
 LESAVKA_SERVER_RC_TETHYS_READY_TIMEOUT_SECONDS=${LESAVKA_SERVER_RC_TETHYS_READY_TIMEOUT_SECONDS:-60}
 LESAVKA_SERVER_RC_TETHYS_SETTLE_SECONDS=${LESAVKA_SERVER_RC_TETHYS_SETTLE_SECONDS:-6}
@@ -508,6 +509,17 @@ true
 REMOTE_SUDO_PRIME
 }
 
+sleep_start_delay() {
+  [[ "${LESAVKA_SERVER_RC_START_DELAY_SECONDS}" != "0" ]] || return 0
+  if [[ ! "${LESAVKA_SERVER_RC_START_DELAY_SECONDS}" =~ ^[0-9]+([.][0-9]+)?$ ]]; then
+    printf 'LESAVKA_SERVER_RC_START_DELAY_SECONDS must be a non-negative number, got %s\n' "${LESAVKA_SERVER_RC_START_DELAY_SECONDS}" >&2
+    exit 64
+  fi
+  echo "==> delaying server-to-RC matrix start for ${LESAVKA_SERVER_RC_START_DELAY_SECONDS}s"
+  echo "   ↪ remote sudo has already been primed; sleeping before prebuild/reconfigure/capture"
+  sleep "${LESAVKA_SERVER_RC_START_DELAY_SECONDS}"
+}
+
 prebuild_probe_tools() {
   [[ "${LESAVKA_SERVER_RC_PROBE_PREBUILD}" != "0" ]] || return 0
   echo "==> prebuilding relay control/analyzer once for the mode matrix"
@@ -1357,9 +1369,11 @@ echo "   ↪ tune_delays=${LESAVKA_SERVER_RC_TUNE_DELAYS} confirm=${LESAVKA_SERV
 echo "   ↪ freshness_limit_ms=${LESAVKA_SERVER_RC_FRESHNESS_MAX_AGE_MS} min_pairs=${LESAVKA_SERVER_RC_FRESHNESS_MIN_PAIRS}"
 echo "   ↪ reconfigure=${LESAVKA_SERVER_RC_RECONFIGURE} strategy=${LESAVKA_SERVER_RC_RECONFIGURE_STRATEGY} allow_gadget_reset=${LESAVKA_SERVER_RC_ALLOW_GADGET_RESET}"
 echo "   ↪ tethys_ready=${LESAVKA_SERVER_RC_WAIT_TETHYS_READY} settle=${LESAVKA_SERVER_RC_TETHYS_SETTLE_SECONDS}s timeout=${LESAVKA_SERVER_RC_TETHYS_READY_TIMEOUT_SECONDS}s preroll_discard=${LESAVKA_SERVER_RC_PREROLL_DISCARD_SECONDS}s"
+echo "   ↪ start_delay=${LESAVKA_SERVER_RC_START_DELAY_SECONDS}s"
 echo "   ↪ artifact_dir=${MATRIX_REPORT_DIR}"
 
 prime_remote_sudo
+sleep_start_delay
 prebuild_probe_tools
 
 IFS=',' read -r -a modes <<<"${LESAVKA_SERVER_RC_MODES}"
diff --git a/testing/tests/client_manual_sync_script_contract.rs b/testing/tests/client_manual_sync_script_contract.rs
index 41e8857..cdc376a 100644
--- a/testing/tests/client_manual_sync_script_contract.rs
+++ b/testing/tests/client_manual_sync_script_contract.rs
@@ -363,6 +363,7 @@ fn server_rc_mode_matrix_validates_advertised_uvc_profiles() {
         "LESAVKA_SERVER_RC_ALLOW_GADGET_RESET=${LESAVKA_SERVER_RC_ALLOW_GADGET_RESET:-1}",
         "LESAVKA_SERVER_RC_RECONFIGURE_VERBOSE=${LESAVKA_SERVER_RC_RECONFIGURE_VERBOSE:-0}",
         "LESAVKA_SERVER_RC_PROMPT_SUDO_EARLY=${LESAVKA_SERVER_RC_PROMPT_SUDO_EARLY:-1}",
+        "LESAVKA_SERVER_RC_START_DELAY_SECONDS=${LESAVKA_SERVER_RC_START_DELAY_SECONDS:-0}",
         "LESAVKA_SERVER_RC_WAIT_TETHYS_READY=${LESAVKA_SERVER_RC_WAIT_TETHYS_READY:-1}",
         "LESAVKA_SERVER_RC_TETHYS_READY_TIMEOUT_SECONDS=${LESAVKA_SERVER_RC_TETHYS_READY_TIMEOUT_SECONDS:-60}",
         "LESAVKA_SERVER_RC_TETHYS_SETTLE_SECONDS=${LESAVKA_SERVER_RC_TETHYS_SETTLE_SECONDS:-6}",
@@ -376,6 +377,11 @@ fn server_rc_mode_matrix_validates_advertised_uvc_profiles() {
         "LESAVKA_SERVER_RC_TUNE_MIN_CHANGE_US=${LESAVKA_SERVER_RC_TUNE_MIN_CHANGE_US:-5000}",
         "Theia sudo password for %s",
         "==> priming remote sudo on ${LESAVKA_SERVER_HOST}",
+        "sleep_start_delay",
+        "==> delaying server-to-RC matrix start for ${LESAVKA_SERVER_RC_START_DELAY_SECONDS}s",
+        "remote sudo has already been primed; sleeping before prebuild/reconfigure/capture",
+        "LESAVKA_SERVER_RC_START_DELAY_SECONDS must be a non-negative number",
+        "start_delay=${LESAVKA_SERVER_RC_START_DELAY_SECONDS}s",
         "==> prebuilding relay control/analyzer once for the mode matrix",
         "LESAVKA_SERVER_RC_MODES=auto",
         "discover_local_webcam_modes",
@@ -451,6 +457,16 @@ fn server_rc_mode_matrix_validates_advertised_uvc_profiles() {
             "server-to-RC mode matrix script should contain {expected}"
         );
     }
+    let prime = SERVER_RC_MODE_MATRIX_SCRIPT
+        .find("prime_remote_sudo\nsleep_start_delay\nprebuild_probe_tools")
+        .expect("matrix should prime remote sudo before delayed start and prebuild");
+    let prompt = SERVER_RC_MODE_MATRIX_SCRIPT
+        .find("Theia sudo password for %s")
+        .expect("matrix should contain the immediate Theia password prompt");
+    assert!(
+        prompt < prime,
+        "password prompt machinery should be defined before the matrix startup sequence"
+    );
 }
 
 #[test]